This download looks like an addon. You need to extract the downloaded zip and put the addon folder in your Garry's Mod addons folder. You should end up with a directory structure similar to below:

• steamapps
  • common
    • garrysmod
      • garrysmod
        • addons
          • Inside.zip <-- Addon folder!
            • e.g.
            • lua
            • maps
            • materials
            • models
            • etc

• Inside.zip/
  • the kuroserver/
    • content/
      • dayandnight/
        • cl_autorun.lua
        • core/
          • cl_hooks.lua
          • sv_hooks.lua
        • entities/
          • effects/
            • ks_rain/
              • cl_autorun.lua
          • entities/
            • ks_daynight/
              • cl_autorun.lua
              • sh_autorun.lua
              • sv_autorun.lua
        • sh_autorun.lua
        • structure/
          • sh_enums.lua
        • sv_autorun.lua
      • garrysmod/
        • lua/
          • autorun/
            • server/
              • rcs_res.lua
          • effects/
            • rg_shelleject/
              • init.lua
            • rg_shelleject_rifle/
              • init.lua
            • rg_shelleject_shotgun/
              • init.lua
          • includes/
            • modules/
              • datastream.lua
              • gmsv_networktables.dll
              • gm_gamedescription.dll
              • gm_tmysql.dll
              • gm_transmittools.dll
              • json.lua
          • nwvar/
            • nwhelper.lua
            • nwvars.lua
            • packet.lua
          • weapons/
            • rcs_57/
              • shared.lua
            • rcs_ak47/
              • shared.lua
            • rcs_aug/
              • shared.lua
            • rcs_awp/
              • shared.lua
            • rcs_base/
              • shared.lua
              • shared.lus
            • rcs_base_1scope/
              • shared.lua
            • rcs_base_autosniper/
              • shared.lua
            • rcs_base_bsnip/
              • shared.lua
            • rcs_base_burst_pistol/
              • shared.lua
            • rcs_base_burst_rifle/
              • shared.lua
            • rcs_base_pistol/
              • shared.lua
            • rcs_base_shotgun/
              • shared.lua
            • rcs_base_silencer_pistol/
              • shared.lua
            • rcs_base_silencer_rifle/
              • shared.lua
            • rcs_beanbag/
              • shared.lua
            • rcs_beanbagscout/
              • cl_init.lua
              • shared.lua
            • rcs_deagle/
              • shared.lua
            • rcs_famas/
              • shared.lua
            • rcs_g3sg1/
              • shared.lua
            • rcs_galil/
              • shared.lua
            • rcs_glock/
              • shared.lua
            • rcs_m249/
              • shared.lua
            • rcs_m3/
              • shared.lua
            • rcs_m4a1/
              • shared.lua
            • rcs_mac10/
              • shared.lua
            • rcs_mp5/
              • shared.lua
            • rcs_p228/
              • shared.lua
            • rcs_p90/
              • shared.lua
            • rcs_paintball/
              • shared.lua
            • rcs_scout/
              • cl_init.lua
              • shared.lua
            • rcs_sg552/
              • shared.lua
            • rcs_tmp/
              • shared.lua
            • rcs_ump/
              • shared.lua
            • rcs_usp/
              • shared.lua
        • resource/
          • fonts/
            • cs.ttf
            • cs.txt
      • libmysql.dll
    • experiment/
      • gamemode/
        • cl_init.lua
        • init.lua
      • gamemount/
        • cl_autorun.lua
        • entities/
          • effects/
            • ks_effect_smoke/
              • cl_autorun.lua
          • entities/
            • ks_boltalternator/
              • cl_autorun.lua
              • sh_autorun.lua
              • sv_autorun.lua
            • ks_boltdynamo/
              • cl_autorun.lua
              • sh_autorun.lua
              • sv_autorun.lua
            • ks_boltgenerator/
              • cl_autorun.lua
              • sh_autorun.lua
              • sv_autorun.lua
            • ks_boltinformer/
              • cl_autorun.lua
              • sh_autorun.lua
              • sv_autorun.lua
            • ks_boltmassproducer/
              • cl_autorun.lua
              • sh_autorun.lua
              • sv_autorun.lua
            • ks_boltmultiplier/
              • cl_autorun.lua
              • sh_autorun.lua
              • sv_autorun.lua
            • ks_boltprotector/
              • cl_autorun.lua
              • sh_autorun.lua
              • sv_autorun.lua
            • ks_breach/
              • cl_autorun.lua
              • sh_autorun.lua
              • sv_autorun.lua
            • ks_broadcaster/
              • cl_autorun.lua
              • sh_autorun.lua
              • sv_autorun.lua
            • ks_doorprotector/
              • cl_autorun.lua
              • sh_autorun.lua
              • sv_autorun.lua
            • ks_radio/
              • cl_autorun.lua
              • sh_autorun.lua
              • sv_autorun.lua
          • weapons/
            • ks_flashgrenade/
              • sh_autorun.lua
            • ks_smokegrenade/
              • sh_autorun.lua
            • ks_stealthcamo/
              • sh_autorun.lua
            • ks_tacgogs/
              • sh_autorun.lua
            • ks_teargrenade/
              • sh_autorun.lua
            • ks_thermalvision/
              • sh_autorun.lua
            • weapon_scout/
              • sh_autorun.lua
        • libraries/
          • sh_achievement.lua
          • sh_perk.lua
        • mounts/
          • emotes/
            • cl_autorun.lua
            • scheme/
              • cl_hooks.lua
              • sh_comm.lua
              • sv_hooks.lua
            • sh_autorun.lua
            • sv_autorun.lua
          • flashlight/
            • cl_autorun.lua
            • entities/
              • weapons/
                • ks_flashlight/
                  • sh_autorun.lua
            • scheme/
              • cl_hooks.lua
              • objects/
                • items/
                  • sh_battery.lua
                  • sh_flashlight.lua
                  • sh_power_node.lua
              • sv_hooks.lua
            • sh_autorun.lua
            • sv_autorun.lua
          • stamina/
            • cl_autorun.lua
            • scheme/
              • cl_hooks.lua
              • objects/
                • attributes/
                  • sh_stamina.lua
                • items/
                  • sh_bottled_water.lua
                  • sh_large_soda.lua
                  • sh_stamina_stimpack.lua
                  • sh_steroids.lua
                  • sh_whiskey.lua
              • sv_hooks.lua
            • sh_autorun.lua
            • sv_autorun.lua
          • storage/
            • cl_autorun.lua
            • entities/
              • entities/
                • ks_locker/
                  • cl_autorun.lua
                  • sh_autorun.lua
                  • sv_autorun.lua
            • scheme/
              • cl_hooks.lua
              • objects/
                • items/
                  • sh_tardis.lua
              • sh_comm.lua
              • sv_hooks.lua
            • sh_autorun.lua
            • sv_autorun.lua
          • writing/
            • cl_autorun.lua
            • entities/
              • entities/
                • ks_paper/
                  • cl_autorun.lua
                  • sh_autorun.lua
                  • sv_autorun.lua
            • scheme/
              • derma/
                • cl_editpaper.lua
                • cl_viewpaper.lua
              • directory/
                • cl_writing.lua
              • objects/
                • items/
                  • sh_paper.lua
              • sv_hooks.lua
            • sh_autorun.lua
            • sv_autorun.lua
        • scheme/
          • classes/
            • sh_survivor.lua
          • cl_hooks.lua
          • derma/
            • cl_achievements.lua
            • cl_perks.lua
          • directory/
            • cl_hotkeys.lua
          • objects/
            • achievements/
              • sh_america.lua
              • sh_anne_boleyn.lua
              • sh_antisocial.lua
              • sh_arnold.lua
              • sh_bastard.lua
              • sh_chameleon.lua
              • sh_gordon_freeman.lua
              • sh_heavily_armored.lua
              • sh_herbal_remedies.lua
              • sh_life_saver.lua
              • sh_nine_eleven.lua
              • sh_northern_rock.lua
              • sh_persistance.lua
              • sh_pure_pwnage.lua
              • sh_sky_diver.lua
              • sh_stella_artois.lua
              • sh_tango_down.lua
              • sh_trader.lua
              • sh_trailer_trash.lua
              • sh_trouble_maker.lua
            • attributes/
              • sh_accuracy.lua
              • sh_acrobatics.lua
              • sh_agility.lua
              • sh_dexterity.lua
              • sh_endurance.lua
              • sh_medical.lua
              • sh_morality.lua
              • sh_strength.lua
            • items/
              • sh_accuracy_stimpack.lua
              • sh_acrobatics_stimpack.lua
              • sh_agility_stimpack.lua
              • sh_ammo_beanbags.lua
              • sh_ammo_buckshot.lua
              • sh_ammo_pistol.lua
              • sh_ammo_smg1.lua
              • sh_ammo_sniper.lua
              • sh_backpack.lua
              • sh_bandage.lua
              • sh_bandit_uniform.lua
              • sh_beer.lua
              • sh_biohazard_uniform.lua
              • sh_bleach.lua
              • sh_bolt_alternator.lua
              • sh_bolt_dynamo.lua
              • sh_bolt_generator.lua
              • sh_bolt_informer.lua
              • sh_bolt_mass_producer.lua
              • sh_bolt_multiplier.lua
              • sh_bolt_protector.lua
              • sh_boxed_backpack.lua
              • sh_boxed_bag.lua
              • sh_boxed_storage_jacket.lua
              • sh_brass_knuckles.lua
              • sh_breach.lua
              • sh_broadcaster.lua
              • sh_canned_beans.lua
              • sh_casual_clothing.lua
              • sh_chinese_takeout.lua
              • sh_clothes_base.lua
              • sh_cyanide.lua
              • sh_dexterity_stimpack.lua
              • sh_door_protector.lua
              • sh_duty_uniform.lua
              • sh_endurance_stimpack.lua
              • sh_freedom_uniform.lua
              • sh_handheld_radio.lua
              • sh_health_kit.lua
              • sh_health_vial.lua
              • sh_helmet.lua
              • sh_kevlar.lua
              • sh_ks_flashgrenade.lua
              • sh_ks_smokegrenade.lua
              • sh_ks_teargrenade.lua
              • sh_medic_uniform.lua
              • sh_melon.lua
              • sh_mercenary_uniform.lua
              • sh_milk_carton.lua
              • sh_milk_jug.lua
              • sh_monolith_uniform.lua
              • sh_resistance_uniform.lua
              • sh_rookie_uniform.lua
              • sh_running_shoes.lua
              • sh_small_bag.lua
              • sh_smart_clothing.lua
              • sh_spray_can.lua
              • sh_stalker_uniform.lua
              • sh_stationary_radio.lua
              • sh_stealthcamo.lua
              • sh_storage_jacket.lua
              • sh_strength_stimpack.lua
              • sh_tactical_goggles.lua
              • sh_tactical_uniform.lua
              • sh_thermal_vision.lua
              • sh_tracksuit_clothing.lua
              • sh_vegetable_oil.lua
              • sh_weapon_ak47.lua
              • sh_weapon_awp.lua
              • sh_weapon_beanbag.lua
              • sh_weapon_beanbag_scout.lua
              • sh_weapon_crowbar.lua
              • sh_weapon_deagle.lua
              • sh_weapon_famas.lua
              • sh_weapon_fiveseven.lua
              • sh_weapon_galil.lua
              • sh_weapon_glock.lua
              • sh_weapon_m249.lua
              • sh_weapon_mac10.lua
              • sh_weapon_mp5.lua
              • sh_weapon_p228.lua
              • sh_weapon_p90.lua
              • sh_weapon_scout.lua
              • sh_weapon_sg552.lua
              • sh_weapon_shotgun.lua
              • sh_weapon_ump.lua
              • sh_weapon_usp45.lua
              • sh_zip_tie.lua
            • perks/
              • sh_angelic_touch.lua
              • sh_army_training.lua
              • sh_assassins_creed.lua
              • sh_bad_dreamer.lua
              • sh_body_builder.lua
              • sh_cannibal.lua
              • sh_carpenter.lua
              • sh_confusing_pockets.lua
              • sh_dayperson.lua
              • sh_demon_ways.lua
              • sh_devils_hands.lua
              • sh_devils_trident.lua
              • sh_divine_intervention.lua
              • sh_doom_soul.lua
              • sh_frozen_tracks.lua
              • sh_garlic_iv.lua
              • sh_godly_muscles.lua
              • sh_gods_will.lua
              • sh_guardian_angel.lua
              • sh_hand_canon.lua
              • sh_healthy_cupboards.lua
              • sh_heavenly_gates.lua
              • sh_hellish_fire.lua
              • sh_holy_priest.lua
              • sh_james_daniels.lua
              • sh_light_step.lua
              • sh_lock_stock.lua
              • sh_master_of_logistics.lua
              • sh_mercantile.lua
              • sh_morale_boost.lua
              • sh_quick_gunner.lua
              • sh_quick_hands.lua
              • sh_robotic_legs.lua
              • sh_roller_skates.lua
              • sh_sandman.lua
              • sh_shield_aura.lua
              • sh_sniper.lua
              • sh_vampire.lua
          • sh_comm.lua
          • sv_hooks.lua
          • vocations/
            • sh_survivor.lua
        • sh_autorun.lua
        • sv_autorun.lua
      • info.txt
    • kuroscript/
      • kuroscript/
        • entities/
          • entities/
            • ks_contraband/
              • cl_init.lua
              • init.lua
              • sh_init.lua
            • ks_currency/
              • cl_init.lua
              • init.lua
              • sh_init.lua
            • ks_item/
              • cl_init.lua
              • init.lua
              • sh_init.lua
            • ks_shipment/
              • cl_init.lua
              • init.lua
              • sh_init.lua
          • weapons/
            • ks_hands/
              • shared.lua
            • ks_keys/
              • shared.lua
        • gamemode/
          • base/
            • cl_autorun.lua
            • scheme/
              • classes/
                • sh_citizen.lua
              • vocations/
                • sh_citizen.lua
            • sh_autorun.lua
            • sv_autorun.lua
          • cl_init.lua
          • frame/
            • cl_autorun.lua
            • scheme/
              • config/
                • sv_config.lua
              • derma/
                • cl_attributes.lua
                • cl_business.lua
                • cl_character.lua
                • cl_directory.lua
                • cl_door.lua
                • cl_inventory.lua
                • cl_menu.lua
                • cl_quiz.lua
                • cl_scoreboard.lua
                • cl_settings.lua
                • cl_storage.lua
                • cl_vocations.lua
                • cl_voice.lua
              • libraries/
                • cl_character.lua
                • cl_chatbox.lua
                • cl_directory.lua
                • cl_door.lua
                • cl_menu.lua
                • cl_player.lua
                • cl_setting.lua
                • cl_storage.lua
                • sh_attribute.lua
                • sh_attributes.lua
                • sh_class.lua
                • sh_command.lua
                • sh_config.lua
                • sh_contraband.lua
                • sh_entity.lua
                • sh_inventory.lua
                • sh_item.lua
                • sh_mount.lua
                • sh_quiz.lua
                • sh_vocation.lua
                • sv_animation.lua
                • sv_chatbox.lua
                • sv_hint.lua
                • sv_player.lua
              • objects/
                • items/
                  • sh_alcohol_base.lua
                  • sh_ammo_base.lua
                  • sh_contraband_base.lua
                  • sh_grenade_base.lua
                  • sh_weapon_base.lua
              • sh_comm.lua
              • sh_enums.lua
              • sh_frame.lua
            • sh_autorun.lua
            • sv_autorun.lua
          • init.lua
          • mounts/
            • animatedlegs/
              • cl_autorun.lua
              • entities/
                • entities/
                  • ks_legs/
                    • cl_autorun.lua
                    • sh_autorun.lua
                    • sv_autorun.lua
              • scheme/
                • sv_hooks.lua
              • sh_autorun.lua
              • sv_autorun.lua
            • areanames/
              • cl_autorun.lua
              • scheme/
                • cl_hooks.lua
                • sh_comm.lua
                • sv_hooks.lua
              • sh_autorun.lua
              • sv_autorun.lua
            • bannedprops/
              • cl_autorun.lua
              • scheme/
                • sv_hooks.lua
              • sh_autorun.lua
              • sv_autorun.lua
            • characterlogs/
              • cl_autorun.lua
              • scheme/
                • directory/
                  • cl_character_logs.lua
                • sh_comm.lua
                • sv_hooks.lua
              • sh_autorun.lua
              • sv_autorun.lua
            • characterviews/
              • cl_autorun.lua
              • scheme/
                • cl_hooks.lua
                • sh_comm.lua
                • sv_hooks.lua
              • sh_autorun.lua
              • sv_autorun.lua
            • cleanedmaps/
              • cl_autorun.lua
              • scheme/
                • sv_hooks.lua
              • sh_autorun.lua
              • sv_autorun.lua
            • displaytyping/
              • cl_autorun.lua
              • scheme/
                • cl_hooks.lua
                • directory/
                  • cl_display_typing.lua
                • sh_enums.lua
              • sh_autorun.lua
              • sv_autorun.lua
            • doorcommands/
              • cl_autorun.lua
              • scheme/
                • sh_comm.lua
                • sv_hooks.lua
              • sh_autorun.lua
              • sv_autorun.lua
            • firespreading/
              • cl_autorun.lua
              • scheme/
                • sh_comm.lua
                • sv_hooks.lua
              • sh_autorun.lua
              • sv_autorun.lua
            • inflationrates/
              • cl_autorun.lua
              • scheme/
                • directory/
                  • cl_inflation_rates.lua
                • sv_hooks.lua
              • sh_autorun.lua
              • sv_autorun.lua
            • observermode/
              • cl_autorun.lua
              • scheme/
                • sh_comm.lua
                • sv_hooks.lua
              • sh_autorun.lua
              • sv_autorun.lua
            • oxygenmeter/
              • cl_autorun.lua
              • scheme/
                • cl_hooks.lua
                • sv_hooks.lua
              • sh_autorun.lua
              • sv_autorun.lua
            • pickupobjects/
              • cl_autorun.lua
              • entities/
                • entities/
                  • ks_grab/
                    • cl_autorun.lua
                    • sh_autorun.lua
                    • sv_autorun.lua
              • scheme/
                • cl_hooks.lua
                • directory/
                  • cl_pickup_objects.lua
                • sv_hooks.lua
              • sh_autorun.lua
              • sv_autorun.lua
            • precipitation/
              • cl_autorun.lua
              • entities/
                • effects/
                  • ks_rain/
                    • cl_autorun.lua
              • scheme/
                • cl_hooks.lua
                • sh_comm.lua
                • sh_enums.lua
                • sv_hooks.lua
              • sh_autorun.lua
              • sv_autorun.lua
            • savecurrency/
              • cl_autorun.lua
              • scheme/
                • sv_hooks.lua
              • sh_autorun.lua
              • sv_autorun.lua
            • saveitems/
              • cl_autorun.lua
              • scheme/
                • sv_hooks.lua
              • sh_autorun.lua
              • sv_autorun.lua
            • spawnpoints/
              • cl_autorun.lua
              • scheme/
                • sh_comm.lua
                • sv_hooks.lua
              • sh_autorun.lua
              • sv_autorun.lua
        • info.txt
    • kuroscript.sql
    • kuroWorks/
      • changelog.txt
      • kuroworks/
        • info.txt
        • lua/
          • autorun/
            • client/
              • cl_kuroworks.lua
            • server/
              • sv_kuroworks.lua
          • kuroworks/
            • client/
              • cl_autorun.lua
              • libraries/
                • cl_string.lua
                • cl_util.lua
            • server/
              • libraries/
                • sv_access.lua
                • sv_command.lua
                • sv_player.lua
                • sv_playerdata.lua
                • sv_util.lua
              • sv_autorun.lua
            • shared/
              • libraries/
                • sh_config.lua
                • sh_hook.lua
                • sh_menu.lua
                • sh_mount.lua
                • sh_player.lua
                • sh_string.lua
                • sh_timer.lua
                • sh_util.lua
              • mounts/
                • admin/
                  • cl_autorun.lua
                  • commands/
                    • sv_!.lua
                    • [email protected]
                    • sv_a.lua
                    • sv_ban.lua
                    • sv_banid.lua
                    • sv_bring.lua
                    • sv_fall.lua
                    • sv_freeze.lua
                    • sv_goto.lua
                    • sv_kick.lua
                    • sv_menu.lua
                    • sv_o.lua
                    • sv_s.lua
                    • sv_send.lua
                    • sv_slay.lua
                    • sv_teleport.lua
                    • sv_unban.lua
                  • sh_autorun.lua
                  • sv_autorun.lua
                • restrict/
                  • cl_autorun.lua
                  • commands/
                    • sv_restrict.lua
                    • sv_restricted.lua
                    • sv_unrestrict.lua
                  • sh_autorun.lua
                  • sv_autorun.lua
                • system/
                  • cl_autorun.lua
                  • commands/
                    • sv_commands.lua
                    • sv_giveaccess.lua
                    • sv_load.lua
                    • sv_mounts.lua
                    • sv_setgroup.lua
                    • sv_unload.lua
                    • sv_who.lua
                  • sh_autorun.lua
                  • sv_autorun.lua
                • voting/
                  • cl_autorun.lua
                  • commands/
                    • sv_vote.lua
                  • sh_autorun.lua
                  • sv_autorun.lua
              • sh_autorun.lua
      • licence.txt
      • todo.txt
    • licence.txt
    • readme.txt
    • todo.txt

Spicysausage_sam2003, shadewiz, Dream Machine, Yakra, spit bitch, Yawn., Cactus, Cromwel, Mr. Conway, [EvoluRP] Thomas